The invention relates to a writing instrument internally housing a miniature electronic calculator which performs an arithmetic operation on numeral data inputted by a key operation.
A conventional desk-top electronic calculator includes ten numerical keys which permit an entry of numbers from 0 to 9, and a plurality of functional keys which choose a selected function. These keys are selectively operated for an intended operation. Because of the number of keys which must be provided, reducing the size of these keys and disposing them closer together for providing a compact calculator results in an increased likelihood of inadvertent entry of information as by operating unintended keys which are located adjacent to an intended key. Thus a miniaturization of the desktop electronic calculator has been limited by the requirements imposed on keyboard switches. It will be convenient if a calculator could be internally housed within a writing instrument since then the result of calculation can be immediately recorded with the writing instrument and since a writing instrument represents an article which a person usually carries about, thus providing a portable calculator. However, a conventional keyboard switch is too large to house an electronic calculator within a writing instrument.
Therefore, it is an object of the invention to provide a writing instrument which internally houses an electronic calculator.
It is another object of the invention to provide a writing instrument with an electronic calculator having a key input section which permits a selective entry of various kinds of information with a single key.
It is a further object of the invention to provide a writing instrument with an electronic calculator which permits a rapid and correct entry of information.